High-Explosive Cratering a Frozen and Unfrozen Soils in Alaska

• Main Author: Smith, North
• Other Authors: COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
• Format: Text
• Language: English
• Published: 1980
• Subjects: Ammunition and Explosives; *ALASKA; *CRATERING; *EXPLOSIVE CHARGES; *TUNDRA; ARMORED PERSONNEL CARRIERS; BURIED OBJECTS; CRATERS; FREEZING; MOISTURE CONTENT; OPTIMIZATION; PERMAFROST; SHALLOW DEPTH; SILT; SOILS; TEST METHODS; THAWING; WEIGHT; HIGH EXPLOSIVE CRATERING; FROZEN GRAVEL; THAWED CONDITIONS; PE62730A; WU003; Anchorage; Fairbanks; Talik; permafrost; Tundra; Alaska
• Online Access: http://www.dtic.mil/docs/citations/ADA084702; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA084702

Explosive cratering tests were conducted in seasonally frozen and thawed gravel at Ft. Richardson near Anchorage, Alaska, and in seasonally frozen and thawed silt overlying permafrost and in silt permafrost at Ft. Wainwright near Fairbanks, Alaska. Explosive charge weights ranged from 26 to 3120 lb and charge burial depths ranged from about 3 to 40 ft. The cube root of the charge weight scaling was used to determine maximum scaled crater dimensions and optimum scaled depth of burial of the charge. Test results for frozen and thawed gravel were essentially the same because of the low moisture content and the relatively shallow depth of freezing (5 to 6 ft). The optimum depth of burial of the charge for maximizing the apparent radius and depth and the true radius was about 1.8 times the cube root of the charge weight for both the frozen and thawed conditions. In seasonally frozen silt overlying a talik and silt permafrost the maximum scaled crater dimensions and optimum scaled burial depths of the charge were smaller than for the thawed condition except for the true crater dimensions. The channeling of energy in the talik produces maximum crater dimensions and an optimum burial depth for the true crater that is larger than for the thawed condition. The results for the homogeneous silt permafrost were very similar to the frozen gravel results with much smaller maximum crater dimensions and smaller optimum charge burial depths than for the thawed silt overlying permafrost.